1. Field of the Invention
The present invention relates to a power device to be mainly mounted on an electrically-powered vehicle such as a hybrid car, a fuel cell car or an electric car.
2. Description of the Related Art
A power device in which a plurality of cells to be secondary cells is coupled rectilinearly to form a battery module and a plurality of battery modules is further connected is used to meet a demand for a large output as in an electrically-powered vehicle. In the power device of this type, a case 70 accommodates a battery module 71 as shown in FIG. 1. The battery module 71 to be accommodated in the case 70 has both ends to which a connecting terminal 72 formed by a screw and a nut is fixed. The battery module 71 fixes a bus bar 73 to the connecting terminal 72 and is connected in series through the bus bar 73. The case 70 has a side portion provided with an end plate 74 including the bus bar 73. The end plate 74 is a plastic molded product and inserts and fixes the bus bar 73 in an insulating state. In the power device having this structure, a setscrew 75 and a nut 76 are screwed into the bus bar 73 of the end plate 74, and connecting the bus bar 73 to the connecting terminal 72 of the battery module 71.
A drawback of the connecting terminal of the above structure is an electric resistance in a connected portion. For the power device in which a large number of battery modules are connected in series and charge/discharge is carried out with a large current, it is important that the electric resistance of the connecting terminal is as low as possible. A high electric resistance considerably increases a loss in power consumed as Joule heat. The electric resistance of the connecting terminal is raised because the nut, the screw and the like are welded to a metal plate. The metal plate, the nut and the like are connected by spot welding. The spot welding has a small contact area. Consequently, the electric resistance of the connected portion is increased.
There has been developed a connecting terminal fabricated by bending and processing a metal plate without welding a nut and a screw (see Japanese Laid-Open Patent Publication No. 1996-287898).